In this photo taken on Friday, Dec. 21, 2012 the Nativity Scene set up in St. Peter's Square at the Vatican that will be unveiled by Pope Benedict XVI Monday, Dec. 24. (AP Photo/Gregorio Borgia)
/ AP

VATICAN CITY 
Pope Benedict XVI has lit a Christmas peace candle set on the windowsill of his private studio.

Pilgrims, tourists and Romans gathered below in St. Peter's Square for the inauguration Monday evening of a Nativity scene and cheered when the flame was lit.

Later, he will appear in St. Peter's Basilica to lead Christmas Eve Mass. The ceremony begins at 10 p.m. (2100 GMT) instead of the midnight start time, which was changed at the Vatican years ago to let the pontiff rest before a Christmas Day speech to be delivered from the basilica's central balcony.